How to dump PHP backtrace on live running script in lldb?

I'm playing around with LLDB (debugger) and I did the following experiment.

1. Run PHP script as:

   php -r "sleep(1000);"
   
   

2. On another console, I've called directly zif_debug_backtrace() from lldb:

   echo 'call (void)zif_debug_backtrace()' | lldb -p $(pgrep -fn php)
   
   

Above worked, however the process stopped with the following warning:

Warning: sleep() expects at most 2 parameters, 1606408648 given in Command line code on line 1
Call Stack:
    0.0016     235152   1. {main}() Command line code:0
    0.0021     235248   2. sleep(1000) Command line code:1

I'm not quite sure why the script had to stop and what I need to do to achieve transparency (without affecting the script)?

P.S. The same happening when calling zif_debug_print_backtrace() and when calling custom_backtrace() it is showing: Backtrace null function called. I'm using xdebug if that change anything.

Maybe I need to call a different function like zend_fetch_debug_backtrace (see: image dump symtab)? Or use the right arguments, if so, which one?

I'm only interested in lldb/gdb solutions in order to print the backtrace.

via Chebli Mohamed